Yeast containing silage inoculants for the enhancement of silage digestion and fermentation in the rumen

ABSTRACT

The invention relates to compositions for use as silage inoculants comprising a yeast strain, one or more bacterial stains, and a suitable carrier. The invention also relates to methods of improving livestock animal silage and meat and milk performance of a livestock animal.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. applicationSer. No. 13/915,254 filed Jun. 11, 2013, which claims priority from U.S.Provisional Application No. 61/658,757 filed Jun. 12, 2012, which ishereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to compositions and methods of preserving silagesuch that aerobic stability is preserved, as well as enhancing ruminalfermentation and digestion to increase animal meat and milk production.

BACKGROUND OF THE INVENTION

Saccharomyces cerevisiae yeast strains are routinely fed to ruminants assupplements to increase meat and milk production. Several theories aredetailed in the literature regarding possible modes of action of yeastin animal performance (Robinson, 2002; Desnoyers et al., 2009). It isprobable that multiple mechanisms may be involved depending upon theprevailing conditions.

However, traditionally, yeasts are considered to be detrimental insilage due to their contribution to aerobic spoilage and dry matterlosses when the silage is exposed to air. Indeed, some Lactobacillusbuchneri inoculants are used to reduce the detrimental yeast populationof silage (U.S. Pat. No. 6,403,084 B1).

Yeast strains that are able to withstand silage conditions and could bedelivered to the animal as the animal consumes silage instead of addedto the diet would greatly increase efficiency and savings for dairy andlivestock producers.

The inventors have developed novel yeast strains and methods of treatingpre-ensiled plant material to deliver such a benefit.

DETAILED DESCRIPTION

The invention consists of live yeast-containing silage inoculants andnovel Saccharomyces cerevisiae yeast strains for use in silage toenhance ruminal fermentation and digestion of silage, thereby improvinganimal productivity.

Viable yeast in the diet can remove products detrimental to rumenstability, scavenge glucose, reduce lactate and prevent drops in pH thatreduce fiber digestion and intake (Guedes et al., 2008; Nocek et al.,2007; Callaway and Martin, 1997). Live yeast may rapidly scavengeresidual oxygen in the rumen, thereby increasing the activity ofobligately anaerobic cellulose digesting bacteria (Newbold et al.,1996). Yeast or yeast by-products may provide nutrients, such as aminoacids, peptides, vitamins, nucleic acids, branched chain VFAs or malate,which are beneficial for growth of ruminal bacteria (Offer, 1990; Martinand Nisbet, 1992; Wallace and Newbold, 1990; Callaway and Martin, 1997),with a subsequent increase in microbial protein flow from the rumen(Offer, 1990; Erasmus et al., 1992; Martin and Nisbet, 1992). Yeast cellwall mannan oligosaccharides reportedly bind with pathogens, mycotoxins,or intestinal cells to protect the intestinal wall and enhance immunestatus of the animal (Swanson, et al., 2002).

Before describing the embodiments of the present invention in detail, itis to be understood that the embodiments of this invention are notlimited to particular compositions or methods of improving digestibilityof ensiled forage, which can, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting.

As used in this specification and the appended claims, the singularforms “a,” “an” and “the” can include plural referents unless thecontent clearly indicates otherwise. Thus, for example, reference to “acomponent” can include a combination of two or more components;reference to “feed” can include mixtures of feed, and the like.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which embodiments of the invention pertain. Many methods andmaterials similar, modified, or equivalent to those described herein canbe used in the practice of the embodiments of the present inventionwithout undue experimentation, the preferred materials and methods aredescribed herein. In describing and claiming the embodiments of thepresent invention, the following terminology will be used in accordancewith the definitions set out below.

The term “inoculation,” as used herein, refers to introduction of viablemicrobes to media or feed plant material.

The term “plant material,” as used herein, refers to material of plantorigin. Feed plant material can be plant material intended to be fed toan animal.

As used herein, “isolated” means removed from a natural source such asfrom uninoculated silage or other plant material.

As used herein, “purified” means that a strain is substantiallyseparated from, and enriched relative to: molds, and/or other yeast orbacterial species or strains found in the source from which it wasisolated.

As used herein, “improved performance” means the increase in the yieldor production of meat, milk, eggs, offspring, or work. It can also referto improved weight gain and feed efficiency of the animal and improvedbody condition.

The term “silage” as used herein is intended to include all types offermented agricultural products such as grass silage, alfalfa silage,wheat silage, legume silage, sunflower silage, barley silage, wholeplant corn silage (WPCS), sorghum silage, fermented grains and grassmixtures, etc.

As used herein, “pre-ensiled plant material” means grasses, maize,alfalfa and other legumes, wheat, sorghum, sunflower, barley, grains,and mixtures thereof, all of which can be treated successfully with theinoculants of the embodiments of the present invention. The inoculantsof the embodiments of the present invention are also useful in treatinghigh moisture corn (HMC).

In an embodiment of the invention the composition contains from about10¹ to about 10¹⁰ viable organisms of the yeast strain per gram of apre-ensiled plant material. In a further embodiment of the invention thecomposition contains from about 10² to about 10⁷ viable organisms of theyeast strain per gram of a pre-ensiled plant material. In yet a furtherembodiment the composition contains from about 10³ to about 10⁶ viableorganisms of the yeast strain per gram of a pre-ensiled plant material.

Suitable carriers are either liquid or solid and are well known by thoseskilled in the art. As non-limiting examples, solid carriers can be madeup of calcium carbonate, starch, cellulose and combinations thereof.

An embodiment of the invention is a biologically pure culture ofSaccharomyces cerevisae, strain YE206, having Patent Deposit No. NRRLY-50734. A further embodiment of the invention is a biologically pureculture of Saccharomyces cerevisae strain YE1241, having Patent DepositNo. NRRL Y-50735. Another embodiment of the invention is a biologicallypure culture of Saccharomyces cerevisae, strain YE1496 having PatentDeposit No. NRRL Y-50736.

The Saccharomyces cerevisiae strains were deposited on Mar. 14, 2012with the Agricultural Research Service (ARS) Culture Collection, housedin the Microbial Genomics and Bioprocessing Research Unit of theNational Center for Agricultural Utilization Research (NCAUR), under theBudapest Treaty provisions. The address of NCAUR is 1815 N. UniversityStreet, Peoria, Ill., 61604. The strain YE206 was given Patent DepositNo. NRRL Y-50734. The strain YE1241 was given Patent Deposit No. NRRLY-50735. The strain YE1496 was given Patent Deposit No. NRRL Y-50736.

The deposits will irrevocably and without restriction or condition beavailable to the public upon issuance of a patent. However, it should beunderstood that the availability of a deposit does not constitute alicense to practice the subject invention in derogation of patent rightsgranted by government action.

A method for treating pre-ensiled plant material to enhance the aerobicstability and digestibility of the resulting silage by adding to thepre-ensiled plant material a digestibility enhancing amount of acomposition containing a yeast strain of the invention, a silagepreserving bacterial strain, and a suitable carrier is also disclosed.

Suitable pre-ensiled plant materials include, but are not limited to:grasses, maize, alfalfa and other legumes, wheat, sorghum, sunflower,barley, grains and mixtures thereof.

Suitable silage preserving bacterial strains include, but are notlimited to: one or more of: Lactobacillus plantarum, L. buchneri, L.alimentarius, L. crispatus, L. paralimentarius, L. brevis, Enterococcusfacium, etc. In one embodiment, the bacterial strains comprise one ormore of: LP286, LP287, LP329, LP346, LP 347, LP 318, LP 319, LN4017,LN4637, LN1391, LN4750, LN1284, LN1286, LN1297, LN1326, LN5665, LP7109or LN5689. See: U.S. Pat. No. 5,747,020; U.S. Pat. No. 6,403,084; U.S.Pat. No. 7,799,551; U.S. Pat. Pub. No. 2009/0028991; U.S. Pat. Pub.No.2009/0028992; U.S. Pat. Pub. No.2008/0138461; U.S. Pat. Pub. No.2009/0028993; U.S. Pat. Pub. No. 2008/0138462; U.S. Pat. Pub.No.2008/1038463, DSM Deposit No: 18113, and DSM Dposit No: 18114.

The composition that is fed to the animal has been treated with aneffective catalytic amount of the yeast strain as is readilydeterminable by those skilled in the art in animal husbandry. Animalspecies that are benefited by embodiments of the present inventioninclude, but are not limited to: ruminant, equine, bovine, porcine,caprine, ovine and avian species, e.g., poultry.

Embodiments of the present invention are further defined in thefollowing Examples. It should be understood that these Examples, whileindicating certain embodiments of the invention, are given by way ofillustration only. From the above discussion and these Examples, oneskilled in the art can ascertain the essential characteristics of thisinvention, and without departing from the spirit and scope thereof, canmake various changes and modifications of the embodiments of theinvention to adapt it to various usages and conditions. Thus, variousmodifications of the embodiments of the invention, in addition to thoseshown and described herein, will be apparent to those skilled in the artfrom the foregoing description. Such modifications are also intended tofall within the scope of the appended claims.

The disclosure of each reference set forth herein is incorporated hereinby reference in its entirety.

EXAMPLE 1 Candidate Yeast Screening

Nine Saccharomyces cerevisiae strains were taken from Pioneer Hi-Bred'smicrobial culture collection of approximately 1700 environmental yeastisolates. Strain uniqueness was confirmed by Hinf I (Roche AppliedScience, Indianapolis, Ind.) digestion of mitochondrial DNA (Querol etal., 1992). Viable yeast cells were evaluated in vitro for effects onruminal fermentation and digestion. Filtered rumen fluid wassupplemented with glucose and inoculated with live yeast cells. Sampleswere incubated at 39 C and pH was monitored over time (2, 4, 6 hr or 4,8, 24 hr depending upon the study). Cotton string digestion was measuredas an indicator of cellulose digestion (Balch, et. al., 1950, Brit. JNutr. 4:389-94).

Yeast isolates YE206, YE1241 and YE1496 were advanced for furthertesting due to rumen fluid pH stabilization and/or cotton stringdigestion. Saccharomyces cerevisiae YE206 was isolated in 1998 fromwhole plant corn silage from Polk City, Iowa. Saccharomyces cerevisiaeYE1241 was isolated in 1998 from European forage. Saccharomycescerevisiae YE1496 was isolated in 2001 from whole plant corn silage fromQuebec, Canada.

EXAMPLE 2 Effects of Yeast Silage Inoculants on Yeast Counts and AerobicStability of Whole Plant Corn Silage and High Moisture Corn Silage

Pioneer® brand corn hybrid 35F44 (36% dry matter) and Dekalb® brand cornhybrid DK61669VT3 (33% dry matter) were harvested and ensiled in 2010and 2011, respectively. High moisture corn grain (69% or 73% dry matter)was harvested from a mixture of corn silage hybrids and ensiled in 2010and 2011, respectively.

Saccharomyces cerevisiae strains YE206, YE1241 and YE1496 were freshlygrown and Lactobacillus plantarum strain LP286 was grown, stabilized andlyophilized as in known in the art. The treatments included control(untreated),

YE206+LP286, YE1241+LP286 and YE1496+LP286. Each yeast strain wasapplied to forage as an aqueous solution to deliver 1×10⁵ CFU/g foragewhen applied at a rate of 2.2 mL/kg. Lactobacillus plantarum LP286 wasused in combination with yeast and applied to deliver 1×10⁴ cfu/g whenapplied at a rate of 2.2 mL/kg. All treatments were applied by syringedispersion, and thoroughly mixed into the forage by shaking in a plasticbag.

For each treatment, two experimental 4″×14″ polyvinyl chloride (PVC)pipe silos were filled and packed at 70% maximum packing density(approximately 160 kg DM/m³), using a hydraulic press. Experimentalsilos were fitted with rubber quick caps at each end, and the top capwas equipped with a Bunsen valve to allow gasses to escape. Silos wereair infused for 24 hours after 28 and 42 days of ensiling to facilitateaerobic instability.

After 60 days of ensiling, silos were emptied and the silage wasthoroughly mixed. Differential yeast counts were conducted on individualtreatment replicates in 2010 and on treatment composites in 2011. Totalyeast counts and Saccharomyces cerevisiaie inoculant yeast recovery wereassessed on BBL™ CHROMagar™ Candida (Sparks, Md.) after 48 to 72 hoursof incubation at 30 degrees Celsius. Individual strain identity wasconfirmed by Hinf I (Roche Applied Science, Indianapolis, Ind.)digestion of mitochondrial DNA of selected colonies (Querol et al.,1992). Aerobic stability assessments were conducted on individualtreatment replicates using the procedure of Honig (Proc. of the Eurobac.Conf., P. Lingvall and S. Lindgren (ed.) (12-16 Aug. 1986) Swed. Univ.of Agric. Sci. Grass and Forage Report No. 3-1990. Pp. 76-81. Uppsala,Sweden.). The time (h) for silage temperature to rise 1.7° C. aboveambient was recorded (ROT). The integration of the area between theactual silage temperature curve and the line drawn by ambienttemperature (Cumm-DD) was calculated during a 7 day time period. Agreater ROT and a lower Cumm-DD is desirable.

Table 1 shows the effects of the inoculants on whole plant corn silageafter 60 days of ensiling. Table 2 shows the effects of the inoculantson high moisture corn silage after 60 days of ensiling. Viable inoculantyeast cells were recovered at silage opening. Inoculant yeast appearedto compete with the native yeast population, since total yeast countswere not altered by yeast inoculation. There were no adverse effects onsilage aerobic stability due to yeast inoculation at the time ofensiling. In high moisture corn silage, aerobic stability was increasedby inoculation with yeast relative to control.

TABLE 1 Effect of yeast inoculants on whole plant corn silage. YE206 +YE1241 + YE1496 + Control LP286 LP286 LP286 Total Yeast, log CFU/g 6.355.10 5.66 4.65* Inoc. Yeast, log CFU/g 0.00 4.56# 3.30* 2.09 ROT, hrs51.00 43.50 37.50 37.50 Cumm-DD, degree-hr 101.46 163.35 171.97 108.10Values expressed as least squares means. *differs from control P ≦ 0.05#differs from control P ≦ 0.01

TABLE 2 Effect of yeast inoculants on high moisture corn silage. YE206 +YE1241 + YE1496 + Control LP286 LP286 LP286 Total Yeast, _(log CFU/g)6.63 6.91 6.75 6.68 Inoc. Yeast, _(log CFU/g) 0.00 6.57# 6.49# 6.75#ROT, _(hrs) 21.00 76.00# 89.00# 88.00# Cumm-DD, _(degree-hr) 256.37175.30 163.36* 120.98# Values expressed as least squares means. *differsfrom control P ≦ 0.05 #differs from control P ≦ 0.01

EXAMPLE 3 Effects of Direct-Fed Yeast Strains on Rumen pH of Steers FedWhole Plant Corn Silage

Dekalb® brand corn hybrid DK61669VT3 (36.4% dry matter) was chopped,processed and ensiled without inoculation in 2011. Approximately 250 kgof forage was packed into each of several tote-boxes by hydraulic press.The net quantity of forage placed in each tote-box was recorded, theplastic liner pulled over the forage and tucked down into the sides ofthe tote-box, and the tote-box was sealed with a lid. After 71 days ofensiling, fistulated Angus steers, averaging approximately 500 kg, werefed 20 kg of wet corn silage per day via Calan® gates. The test dietconsisted of 95% whole plant corn silage and 5% protein supplement on adry matter basis. The animals had access to fresh water and salt/mineralblocks at all times. Each steer was fed 50% of their diet at 12 hintervals. The silage at each feeding was top-dressed with either 0(control) or 1×10⁹ yeast cells in a 5 gm maltodextrin carrier for atarget feeding rate of 2×10⁹ yeast cells per animal per day. The yeaststrains were grown, stabilized and lyophilized as in known in the art.Dead yeast cells were generated by heating rehydrated yeast samples at80 degree Celsius for 1 hour. Killed cells were again lyophilized priorto mixing with maltodextrin. Yeast viability and cell counts wereassessed via flow cytometer BacLight™ Bacterial Viability Kit (LifeTechnologies, Grand Island, N.Y.). The trial was performed as a 4 by 4Latin Square with 14 day periods. Rumen pH measurements were taken at 15minute intervals with Kahne Limited (Auckland, New Zealand) rumen sensorboluses. Means were averaged over the final 7 days of each period.Hourly values were averages of 15 min means before and after each hourwithin the day. Boluses were removed, data downloaded and sensorsrecalibrated at the end of each period.

Table 3 shows the effects of direct-fed yeast supplementation on steerrumen pH. Steers were fed at 8:00 AM and 8:00 PM. At three to sevenhours post-feeding, rumen pH was often higher when diet contained liveyeast. Live yeast tended to retard the post-feeding drop in pH and speedpH recovery. Mean rumen pH was significantly higher in steers fed liveyeast strains YE206 and YE1496 versus control steers or steers fed deadyeast strain YE1496. While not bound to one particular yeast mode ofaction, alteration in rumen pH in response to direct-fed Saccharomycescerevisiae strains demonstrates rumen modulation capability.

TABLE 3 Mean rumen pH of steers fed whole plant corn silage with orwithout direct-fed yeast supplementation. Time of YE206 YE1496 YE1496Day Control Live Live Dead 12:00 PM 6.187 6.433 6.424 6.392  1:00 AM6.276 6.514 6.533 6.442  2:00 AM 6.445 6.614 6.610 6.459  3:00 AM 6.6516.718 6.718 6.537  4:00 AM 6.684 6.732 6.733 6.647  5:00 AM 6.727 6.7416.820 6.727  6:00 AM 6.823 6.770 6.872 6.799  7:00 AM 6.879 6.872 6.9246.858  8:00 AM 6.743 6.796 6.724 6.688  9:00 AM 6.501 6.533 6.439 6.42910:00 AM 6.287 6.423 6.340 6.242 11:00 AM 6.146 6.355 6.277 6.150 12NOON 6.101 6.303 6.326 6.188  1:00 PM 6.186 6.317 6.378 6.331  2:00 PM6.420 6.491 6.522 6.515  3:00 PM 6.516 6.626 6.669 6.576  4:00 PM 6.6066.757 6.737 6.662  5:00 PM 6.698 6.803 6.808 6.726  6:00 PM 6.788 6.8826.871 6.781  7:00 PM 6.824 6.926 6.917 6.862  8:00 PM 6.729 6.786 6.7696.721  9:00 PM 6.500 6.517 6.444 6.403 10:00 PM 6.316 6.491 6.459 6.27911:00 PM 6.196 6.435 6.404 6.301 Mean 6.509^(b) 6.618^(a) 6.613^(a)6.530^(b) SE = 0.026 ^(ab)Means not sharing a common superscript differ(P < 0.05)

Having illustrated and described the principles of the embodiments ofthe present invention, it should be apparent to persons skilled in theart that the embodiments of the invention can be modified in arrangementand detail without departing from such principles. We claim allmodifications that are within the spirit and scope of the appendedclaims.

All publications and published patent documents cited in thisspecification are incorporated herein by reference to the same extent asif each individual publication or published patent document wasspecifically and individually indicated to be incorporated by reference.

REFERENCES

Balch, C. C, and W. V. Johnson. 1950. Factors affecting the utilizationof food by dairy cows; factors influencing the rate of breakdown ofcellulose (cotton thread) in the rumen of the cow. Brit. J Nutr.4:389-94.

Callaway, E. S. and Martin, S. A. (1997). Effects of a Saccharomycescerevisiae culture on ruminal bacteria that utilize lactate and digestcellulose. J. Dairy Sci. 80, 2035-2044.

Desnoyers, M., Giger-Reverdin, S., Bertin, G., Duvaux-Ponter, C. andSauvant, D. (2009). Meta-analysis of the influence of Saccharomycescerevisiae supplementation on ruminal parameters and milk production ofruminants. J. Dairy Sci. 92, 1620-1632.

Erasmus, L. J., Botha, P. M. and Kistner, A. (1992). Effect of yeastculture supplementation on production, rumen fermentation and duodenalmicrobial flow in dairy cows. J. Dairy Sci. 75, 3056-3065.

Guedes, C. M.; Goncalves, M. A. M.; Rodrigues, A.; Dias-da-Silva. A.(2008). Effects of a Saccharomyces cerevisiae yeast on ruminalfermentation fibre degradation of maize silages in cows. Animal FeedSci, and Tech. 145, 27-40.

Martin, S. A. and Nisbet, D. J. (1992). Effects of direct fed microbialson rumen microbial fermentation. J. Dairy Sci. 75 1736-1744

Newbold, C. J., McIntosh, F. M., and Wallace, R. J. (1996). Mode ofaction of yeast Saccharomyces cerevisiae as a feed additive forruminants. Brit. J. Nutr. 76 249-261.

Nocek, J. E., Holt, M. G. and Oppy, J. (2007). Effects ofsupplementation with yeast cultures and enzymatically hydrolyzed yeaston performance of early lactation dairy cattle. J. Dairy Sci. 94,4046-4056.

Offer, N. W. (1990). Maximizing fiber digestion in the rumen: the roleof yeast culture. In Biotechnology in the Feed Industry, ed. T. P.Lyons, Alltech Technical Publications, Nicholasville, Ky., pp. 79-96.

Querol, A., Barrio, E., and Ramon, D. (1992). A Comparative Study ofDifferent Methods of Yeast Strain Characterization. Systematic and Appl.Microbiol. 15, 439-446.

Robinson, P. H. (1992) see World Wide Web (www):animalscience.ucdavis.edu/faculty/robinson/Articles/FullText/pdf/VVeb200901.pdf.

Swanson, K.; Grieshop, C.; Flickinger, E.; Bauer, L.; Healy, H.; Dawson,K.; Merchen, N. and Fahey, Jr, C. (2002).SupplementalFructooligosaccharides and Mannanoligosaccharides Influence ImmuneFunction, Ileal and Total Tract Nutrient Digestibilities, MicrobialPopulations and Concentrations of Protein Catabolites in the Large Bowelof Dogs. The Journal of Nutrition, 980-989.

Wallace, R. J. and Newbold, C. J. (1992). Probiotics for ruminants. InProbiotics: The Scientific Basis, ed. R. Fuller. Chapman and Hall,London, pp. 317-353.

What is claimed is:
 1. A composition for use as a silage inoculantcomprising: a yeast strain, one or more bacterial strains, and asuitable carrier.
 2. The composition of claim 1, wherein the yeaststrain is one or more of: Saccharomyces cerevisiae strain YE206,deposited as Patent Deposit No. NRRL Y-50734; S. cerevisiae strainYE1241, deposited as Patent Deposit No. NRRL Y-50735; or S. cerevisiaestrain YE1496, deposited as Patent Deposit No. NRRL Y-50736.
 3. Thecomposition of claim 1, wherein the bacterial strains comprise one ormore of: Lactobacillus plantarum, L. buchneri, L. alimentarius, L.crispatus, L. paralimentarius, L. brevis, or Enterococcus facium andmixtures thereof.
 4. The composition of claim 3 wherein the bacterialstrains comprise one or more of: LP286, LN4017, LN4637, LP329, LP7109 orLN5689 and mixtures thereof.
 5. The composition of claim 1, wherein thecomposition contains from about 10¹ to about 10¹⁰ viable organisms ofsaid yeast strain per gram of a pre-ensiled plant material.
 6. Thecomposition of claim 5, wherein the composition contains from about 10³to about 10⁶ viable organisms of said yeast strain per gram of saidpre-ensiled plant material.
 7. A method for treating pre-ensiled plantmaterial, the method comprising adding thereto: a yeast strain, one ormore bacterial stains, and a suitable carrier.
 8. The method of claim 7,wherein the yeast strain is any one of: Saccharomyces cerevisiae strainYE206, deposited as Patent Deposit No. NRRL Y-50734; S. cerevisiaestrain YE1241, deposited as Patent Deposit No. NRRL Y-50735; or S.cerevisiae strain YE1496, deposited as Patent Deposit No. NRRL Y-50736.9. The method of claim 7, wherein the bacterial strains comprise one ormore of: Lactobacillus plantarum, L. buchneri, L. alimentarius, L.crispatus, L. paralimentarius, L. brevis, and Enterococcus facium andmixtures thereof.
 10. The method of claim 9 wherein the bacterial straincomprises or more of: LP286, LN4017, LN4637, LP329, LP7109 or LN5689 andmixtures thereof.
 11. The method of claim 7, wherein the compositioncontains from about 10¹ to about 10¹⁰ viable organisms of said yeaststrain per gram of a pre-ensiled plant material.
 12. The method of claim11, wherein the composition contains from about 10³ to about 10⁶ viableorganisms of said yeast strain per gram of said pre-ensiled plantmaterial.
 13. The method of claim 7, wherein the pre-ensiled plantmaterial is selected from the group consisting of grasses, maize,alfalfa, wheat, legumes, sorghum, sunflower, barley, grains, andmixtures thereof.
 14. A method of improving meat and milk performance ina livestock animal, the method comprising feeding the livestock animalsilage treated with an inoculant comprising: pre-ensiled plant material,a yeast strain, one or more bacterial stains, and a suitable carrier.15. The method of claim 14, wherein the yeast strain is any one of:Saccharomyces cerevisiae strain YE206, deposited as Patent Deposit No.NRRL Y-50734; S. cerevisiae strain YE1241, deposited as Patent DepositNo. NRRL Y-50735; or S. cerevisiae strain YE1496, deposited as PatentDeposit No. NRRL Y-50736.
 16. The method of claim 14, wherein thebacterial strains comprise one or more of: Lactobacillus plantarum, L.buchneri, L. alimentarius, L. crispatus, L. paralimentarius, L. brevis,or Enterococcus facium and mixtures thereof.
 17. The method of claim 16wherein the bacterial strain comprises one or more of: LP286, LN4017,LN4637, LP329, LP7109 or LN5689 and mixtures thereof.
 18. The method ofclaim 14, wherein the composition contains from about 10¹ to about 10¹⁰viable organisms of said yeast strain per gram of a pre-ensiled plantmaterial.
 19. The method of claim 18, wherein the composition containsfrom about 10³ to about 10⁶ viable organisms of said yeast strain pergram of said pre-ensiled plant material.
 20. The method of claim 14,wherein the pre-ensiled plant material is selected from the groupconsisting of grasses, maize, alfalfa, wheat, legumes, sorghum,sunflower, barley, grains, and mixtures thereof.
 21. A substantiallypurified strain of yeast selected from the group consisting of:Saccharomyces cerevisiae strain YE206, deposited as Patent Deposit No.NRRL Y-50734; S. cerevisiae strain YE1241, deposited as Patent DepositNo. NRRL Y-50735; or S. cerevisiae strain YE1496, deposited as PatentDeposit No. NRRL Y-50736.
 22. The yeast strain of claim 21 which isYE206, deposited as Patent Deposit No. NRRL Y-50734.
 23. The yeaststrain of claim 21 which is YE1241, deposited as Patent Deposit No. NRRLY-50735.
 24. The yeast strain of claim 21 which is YE1496, deposited asPatent Deposit No. NRRL Y-50736.